Seac Ninfa Sws Diving Bcd Vest Material outer bladder: PU-coated Nylon 840 D. Material inner bladder: PU-coated Nylon 420 D Dump valves: 3 with manual commands D-rings: 4  40 mm rings in stainless steel + 2  25 mm rings in technopolymer Dry weight (size M): 3100 g (complete with hose and weight pockets).